The purpose of this study was to find out the effect of Bloom’s vs. Fink’s taxonomy on the students’ achievement in science proficiency at primary level in Pakistan as compared to the traditional teaching method. This study was conducted in a posttest only format; where both the experimental and one control group were subjected to a post intervention assessment. In this study (n=30) 5th grade students were randomly selected. From those (n=30) students, three groups were made: Control group, Experimental group 1, and Experimental group 2; with each group encompassing (n=10) students. The students were selected by a random sampling technique. Control group was taught by the usual traditional method that their science instructor had been using to teach them, whereas, both the experimental groups 1 and 2 were taught by Bloom’s and Fink’s taxonomy respectively, for one science lesson. The data that was obtained from the posttest activity worksheet was statically analyzed through a paired samples t-test for further scrutiny. The results obtained exhibited significantly higher achievement in science proficiency by both the experimental groups when compared to the traditional method’s results, but when compared to each other, the results were not significantly different. This study has implications for action researchers and teachers to independently apply the two taxonomies to check the variance in the proficiency of their students over a longer period of time.